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Lipopolysaccharide induced connective tissue growth factor gene expression in human bronchial epithelial cells
Author(s) -
NISHIOKA Michiyoshi,
OGAWA Emiko,
KINOSE Daisuke,
HARUNA Akane,
OHARA Tadashi,
ITO Isao,
HOSHINO Yuma,
ITO Yutaka,
MATSUMOTO Hisako,
NIIMI Akio,
MIO Tadashi,
CHIN Kazuo,
HIRAI Toyohiro,
MURO Shigeo,
MISHIMA Michiaki
Publication year - 2010
Publication title -
respirology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 85
eISSN - 1440-1843
pISSN - 1323-7799
DOI - 10.1111/j.1440-1843.2010.01742.x
Subject(s) - ctgf , growth factor , connective tissue , respiratory epithelium , medicine , lipopolysaccharide , gene expression , transforming growth factor , epithelium , biology , microbiology and biotechnology , cancer research , pathology , gene , biochemistry , receptor
Background and objective: Connective tissue growth factor (CTGF) is up‐regulated in the lungs of patients with chronic obstructive pulmonary disease (COPD). Cigarette smoke and repeated bacterial infections, both of which are rich sources of LPS, are major causes of COPD. The high levels of LPS in lung epithelial lining fluid also suggest that it may have a considerable impact on the airway epithelium, in terms of cytokine and growth factor production. The aim of this study was to clarify the mechanism of LPS‐induced CTGF expression in bronchial epithelial cells. Methods: The expression and transcriptional regulation of the CTGF gene were assessed using the cultured human bronchial epithelial cell line, BEAS‐2B. Results: LPS significantly up‐regulated CTGF mRNA expression in a dose‐dependent fashion, with 100 µg/mL LPS causing a twofold increase after 2 h. CTGF protein expression was also up‐regulated by LPS after 8 h. Transforming growth factor‐β1 mRNA expression was not changed by LPS treatment. A pharmacological inhibitor of nuclear factor (NF)‐κB, MG132, inhibited LPS‐induced CTGF mRNA expression. Furthermore, luciferase assays demonstrated that deletion of base pairs −253 to −53 from the CTGF promoter, where the Smad and proximal NF‐κB binding sites are located, decreased the induction of CTGF by LPS. After stimulation with LPS, the p65 subunit of NF‐κB was shown to be bound to the CTGF promoter in vitro and in situ . Conclusions: LPS directly induced CTGF expression in bronchial epithelial cells, independently of transforming growth factor‐β1, suggesting a possible mechanism for airway remodelling in COPD that is induced by smoking and repeated bacterial infections.